I can’t begin to
tell you how impressed I was, when I was first learning Smalltalk, to
discover that programs were themselves built out of objects, and that you
could change and extend these too, just like an other. It’s a big part of why
I’m still here, and standing before you today.

(Give a brief
rundown of what these do at runtime)…

There is really very
little that you can’t get at in Smalltalk. We identified the things you can’t
override back in ’89: sending a message, receiving a message, returning from
a context, and reading and writing instance variables.